X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fdynamic%2Fcnv.ma;h=bde05a33cabcc6d4ee858568f74563abdaeb164d;hp=97c1feca2ff0271bf2794c13797b2a8ee76b5799;hb=9aa2722ff4aa7868ffd14e5a820cd6dc79e2c8a6;hpb=19a25bf176255055193372554437729a6fa1894c

diff --git a/matita/matita/contribs/lambdadelta/basic_2/dynamic/cnv.ma b/matita/matita/contribs/lambdadelta/basic_2/dynamic/cnv.ma
index 97c1feca2..bde05a33c 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/dynamic/cnv.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/dynamic/cnv.ma
@@ -140,6 +140,17 @@ lemma cnv_inv_cast (a) (h): ∀G,L,U,T. ⦃G, L⦄ ⊢ ⓝU.T ![a, h] →
                                   ⦃G, L⦄ ⊢ U ➡*[h] U0 & ⦃G, L⦄ ⊢ T ➡*[1, h] U0.
 /2 width=3 by cnv_inv_cast_aux/ qed-.
 
+(* Basic forward lemmas *****************************************************)
+
+lemma cnv_fwd_flat (a) (h) (I) (G) (L):
+                   ∀V,T. ⦃G, L⦄ ⊢ ⓕ{I}V.T ![a,h] →
+                   ∧∧ ⦃G, L⦄ ⊢ V ![a,h] & ⦃G, L⦄ ⊢ T ![a,h].
+#a #h * #G #L #V #T #H
+[ elim (cnv_inv_appl … H) #n #p #W #U #_ #HV #HT #_ #_
+| elim (cnv_inv_cast … H) #U #HV #HT #_ #_
+] -H /2 width=1 by conj/
+qed-.
+
 (* Basic_2A1: removed theorems 6:
               snv_fwd_da snv_fwd_lstas snv_cast_scpes
               shnv_cast shnv_inv_cast snv_shnv_cast